1. Field of the Invention
The present invention relates to a floating nut which can be fastened at a high torque.
2. Description of the Related Art
In a case wherein components which are to be joined with each other after completion of manufacture are produced individually at predetermined dimensions, such as a satellite capsule of a space rocket and the rocket body, a so-called floating nut is generally used as a joining member to allow adjustment of dimensional difference occurred during the manufacturing process within a given tolerance when joining the respective components.
FIG. 4 shows a plan view of a conventional floating nut, and FIG. 5 shows a side plan view of the floating nut partly in section. A conventional floating nut 1 comprises a retainer 2 formed by folding a plate into a convex shape and a nut 3. The retainer 2 is folded in a convex shape as shown in FIG. 5, and holes 2a are opened at both ends thereof so as to pass a rivet, etc. to fix the retainer 2 to one of components to be joined with each other. Further, an opening 2b is formed in a center portion of the retainer 2, which is formed at a higher stage than both ends having the holes 2a, so as to pass the nut 3, and the retainer 2 has a width gradually increasing as approaching to the center thereof as shown in FIG. 4.
The nut 3 with a flange 3c is a 12-point nut and can be explained as that it has a shape of an external diameter in which coaxial hexagons of the same dimension are mutually deviated by 30xc2x0. The nut 3 has a caulking portion 3d, which is to be elliptically caulked after the nut 3 is engaged with a corresponding bolt (not shown), whereby a female screw 3e of the nut 3 can be firmly fixed to a male screw of the bolt resulting in a high tightening torque.
In addition, the opening 2b of the retainer 2 has twelve recesses 2c formed at equal spacing corresponding to projections 3a of the nut 3. Twelve protrusions 2d located between the recesses 2c are abutted on the projections 3a of the nut 3 while ensuring a predetermined clearance to the projections 3a of the nut 3 by the recesses 2c, and the rotational angle of the nut 3 with respect to the retainer 2 within the opening 2b can be limited.
In the manufacturing process of the floating nut 1, the nut 3 is prevented from falling out from the opening 2b of the retainer 2 by caulking an upper end 3b of the projection 3a so that the upper end 3b protrudes from the recess 2c of the opening 2b after the nut 3 is passed through the opening 2b of the retainer 2 as shown in FIG. 5.
When the retainer 2 of the floating nut 1 is fixed to one of the components which are joined, the nut 3 becomes eccentric with respect to the retainer 2 by the clearance between the recess 2c of the opening 2b and the projection 3a of the nut 3 thereby being able to adjust the positional deviation to the bolt positioned by the other joined component achieving a reliable joining.
However, the conventional floating nut 1 included the following problems. In order to prevent the nut 3 from falling out from the opening 2b of the retainer 2, the upper end 3b of the projection 3a is caulked so that the upper end 3b protrudes from the recess 2c of the opening 2b in the floating nut 1 as shown in FIG. 5. However, the amount of the protrusion by means of the caulking is naturally limited. As a result, the clearance between the projection 3a of the nut 3 and the recess 2c of the retainer 2 is required to be kept at an amount less than the amount of the protrusion protruded by the caulking.
The clearance between the projection 3a of the nut 3 and the recess 2c of the retainer 2 has a direct relation in the floating amount of the nut 3 with respect to the retainer 2. Thus, in the conventional floating nut 1 it has been possible to obtain only a small floating amount and cover only a limited dimensional difference meaning that opportunity of application was limited.
The present invention has been made in light of the above problems. It is an object of the present invention to widen the opportunity of application of a floating nut by increasing the amount of floating of the floating nut which supports a nut with a retainer by floating.
In order to solve the above problems, according to a first aspect of the present invention, in a floating nut to support a nut passed through an opening of a retainer by floating with respect to the retainer, the nut comprises a protrusion and a recess having a predetermined difference in diameter on an outer circumferential surface, a flange of the outside diameter not less than the diameter of an opening of the retainer on a bottom, and a stop ring of the outside diameter not less than the diameter of the opening of the retainer at the height separated from the flange by at least the thickness of the opening portion of the retainer in an attachable/detachable manner, and the opening of the retainer is of the analogous shape ensuring a desired clearance with respect to the protrusion and the recess on the outer circumferential surface of the nut.
According to the present invention, the opening of the retainer has a shape analogous to the circumferential surface of the nut whereby a desired clearance between the opening of the retainer and the circumferential surface of the nut is secured, and thus the nut can be eccentric by the clearance. The nut further comprises the flange having the outside diameter not less than the diameter of the opening of the retainer on the bottom, and the stop ring having the outside diameter not less than the diameter of the opening of the retainer at the height separated from the flange by at least the thickness of the opening portion of the retainer in an attachable/detachable manner, and the nut is movable in the axial direction with respect to the retainer. The axially movable range of the nut with respect to the retainer is limited by the flange and the stop ring, and the nut is prevented from being detached from the retainer.
According to a second aspect of the present invention, in the floating nut according to the first aspect of the present invention, the clearance between the circumferential surface of the nut and the opening of the retainer analogous to the circumferential surface of the nut is determined according to the required floating amount.
According to the present invention, the desired floating amount can be secured since the clearance between the circumferential surface of the nut and the opening of the retainer analogous to the circumferential surface of the nut is determined according to the required floating amount. Also, in the present invention, the axially movable range of the nut with respect to the retainer is limited by the flange and the stop ring, and thus, the nut is prevented from falling out from the retainer.
According to a third aspect of the present invention, in the floating nut according to the first aspect of the present invention, the clearance between the protrusion and the recess of the nut and the analogous opening of the retainer is set to be greater than 1.52 mm.
According to the present invention, the clearance between the protrusion and the recess of the nut and the analogous opening of the retainer is set to be greater than 1.52 mm, and the floating amount greater than 0.76 mm in one direction can be obtained. Also, in the present invention, the axially movable range of the nut with respect to the retainer is limited by the flange and the stop ring, and thus, the nut is prevented from falling out from the retainer.
According to a fourth aspect of the present invention, in the floating nut according to any one of the first to third aspects of the present invention, the protrusion and the recess provided on the outer circumferential surface of the nut form the spline.
In the present invention, the protrusion and recess having a predetermined difference in diameter are obtained on the outer circumferential surface of the nut by the protruded and recessed shape of the spline. According to the present invention, the opening of the retainer forms the spline ensuring a desired clearance for the protrusion and recess on the outer circumferential surface of the nut, and the nut can be eccentric against the retainer by the clearance. Also in the present invention, the axially movable range of the nut with respect to the retainer is limited by the flange and the stop ring, and the nut is prevented from falling out from the retainer.
According to a fifth aspect of the present invention, in the floating nut according to any one of the first to fourth aspects of the present invention, the protrusion and recess provided on the outer circumferential surface of the nut have a groove so as to fit the stop ring therein.
In the present invention, the protrusion and recess provided on the outer circumferential surface of the nut have a groove to fit the stop ring therein, and the stop ring can be correctly positioned. Also, the stop ring is prevented from being detached therefrom.
According to a sixth aspect of the present invention, in the floating nut according to any one of the first to fifth aspects of the present invention, the nut has a caulking portion.
In the present invention, the female screw of the nut is firmly and closely attached to the male screw of the bolt by means of the caulking portion caulked in an elliptic shape after the nut is engaged with the bolt corresponding thereto and then locked, whereby a high tightening torque can be obtained.
According to a seventh aspect of the present invention, in the floating nut according to any one of the first to sixth aspects of the present invention, the retainer is a plate-like component folded in a convex shape.
According to the present invention, the nut has the stop ring at the height separated by the distance of not less than the thickness of the plate-like component from the flange, and the nut is movable in the axial direction with respect to the retainer. The axially movable range of the nut with respect to the retainer is limited by the flange and the stop ring, and the nut is prevented from being pulled out from the retainer.
According to an eighth aspect of the present invention, in the floating nut according to any one of the first to seventh aspects of the present invention, the retainer and the nut are surface treated to prevent galling between the protrusion and recess and the analogous opening, and further to prevent generation of rust.
According to the present invention, the galling between the protrusion and recess of the nut and the opening of the retainer being similar to the protrusion and recess of the nut, and generation of rust on the retainer and the nut can be effectively suppressed.